Currently there exists no valid and reliable method of objectively quantifying an individual's experience of pain (Younger J et al, Pain Outcomes: A Brief Review of Instruments and Techniques. Curr Pain Headache Rep., 2009 February; 13(1):39-43). In the United States, approximately 100 million adults—more than the number affected by heart disease, diabetes, and cancer combined—suffer from common chronic pain conditions (Tsang, A et al, Common chronic pain conditions in developed and developing countries: Gender and age differences and comorbidity with depression-anxiety disorders. Journal of Pain. 2008; 9(10):883-891) with an annual national economic cost associated with chronic pain estimated to be $560-635 billion in 2011. The aging of the United States population means that a growing number of Americans will experience the diseases with which chronic pain is associated—diabetes, cardiovascular disorders, arthritis, and cancer, among others (Cherry et al, Population aging and the use of office-based physician services. NCHS Data Brief, No. 41. Hyattsville, Md.: National Center for Health Statistics). Increases in obesity will result in more orthopedic problems related to the degradation of cartilage (Richettel et al., 2011). As a result, there will be a greater number of joint replacement surgeries, occurring in younger adult populations (Harms, S., R. Larson, A. E. Sahmoun, and J. R. Beal. 2007. Obesity increases the likelihood of total joint replacement surgery among younger adults. International Orthopaedics 31(1):23-26; Changulani et al., 2008); resulting in associated acute and also potentially chronic pain. Increases in disease states associated with pain will not only be experienced in the US. A UK Report from 2009, stated that, “chronic pain is two to three times more common now than it was 40 years ago” (U.K. Department of Health. 2009. 150 years of the chief medical officer: On the state of public health. Annual Report. London: U.K. Department of Health; PAGE 34). There is no question that pain, and other complex chronic disease states, are a major public health challenge. According to the Institute of Medicine's 2011 study—Relieving Pain in America: A Blueprint for Transforming Prevention, Care, Education, and Research., pain is a uniquely individual and subjective experience that depends on a variety of biological, psychological, and social factors, and different population groups experience pain differentially (IOM (Institute of Medicine). 2011. Relieving Pain in America: A Blueprint for Transforming Prevention, Care, Education, and Research. Washington, D.C.: The National Academies Press.). Why one person suffers an injury and reports modest pain and another with a similar injury reports serious pain depends on many factors: genetic characteristics, general health status and comorbidities, pain experiences from childhood on, the brain's processing system, the emotional and cognitive context in which pain occurs, and cultural and social factors. Costly procedures often are performed when other actions should be considered, such as prevention, counseling, and facilitation of self-care, which are common features of successful treatment. In addition, adequate pain treatment and follow-up may be thwarted by a mix of uncertain diagnosis and societal stigma consciously or unconsciously applied to people reporting pain, particularly when they do not respond readily to treatment (IOM (Institute of Medicine). 2011. Relieving Pain in America: A Blueprint for Transforming Prevention, Care, Education, and Research. Washington, D.C.: The National Academies Press). For these reasons, it is important to develop an objective manner to measure pain, and general physical symptoms, but then to further combine and analyze sensor acquired data with additional factors that influence the individual experience of pain, and other related healthcare issues and disease states. Currently, physicians and caregivers rely upon a patient's own description of symptoms such as pain, which is an example of a physical outcome that has defied objective measurement. Today, uni-dimensional scales are used to evaluate pain. A commonly used scale is the numerical rating scale (NRS), which typically consists of scores 0-10, with the far left denoting “no pain” and the far right end of the scale as “worst pain imaginable”. In general, it is difficult for a subject to accurately describe their pain, but especially while under duress, or for example patient populations that may struggle with communication, such as children, elderly patients suffering from dementia, and those who do not speak the same language as the treating medical professional. Clinical findings that can be seen—a broken bone on an x-ray, for example—do not necessarily correlate well with the severity of pain the patient perceives. Elderly patients experience pain twice as often as those under the age of 60 which is thought to relate to their inability to accurately communicate pain and intensity or source of pain (Herr K et al, Assessment and measurement of pain in older adults. Clin Geriatric Med, 2001 August; 17(3):457-vi) (Weiner D et al, 1999. Pain in nursing home residents: An exploration of prevalence, staff perceptions, and practical aspects of measurement. Clin of J Pain. 1999; 15:92 [PubMed: 10382922]). People afflicted by pain may find the rough tools of language inadequate to convey the character and intensity of their experience and its significance to them. This can be a substantial barrier to obtaining adequate treatment (Werner, A., and K. Malterud. 2003. It is hard work behaving as a credible patient: Encounters between women with chronic pain and their doctors. Social Science & Medicine 57(8):1409-1419). According to the Institute of Medicine, (IOM, 2011), pain and its severity, how it evolves, and the effectiveness of treatment depend on a constellation of biological, psychological, and social factors, such as the following:                Biological—the extent of an illness or injury and whether the person has other illnesses, is under stress, or has specific genes or predisposing factors that affect pain tolerance or thresholds;        Psychological—anxiety, fear, guilt, anger, depression, and thinking the pain represents something worse than it does and that the person is helpless to manage it (Ochsner, K., J. Zaki, J. Hanelin, D. Ludlow, K. Knierim, T. Ramachandran, G. Glover, and S. Mackey. 2008. Your pain or mine? Common and distinct neural systems supporting the perception of pain in self and other. Social Cognitive and Affective Neuroscience 3(2):144-160);        Social—the response of significant others to the pain—whether support, criticism, enabling behavior, or withdrawal—the demands of the work environment, access to medical care, culture, and family attitudes and beliefs.Beyond the lack of a currently available objective measures for pain and more recent agreement that pain, and other complex chronic diseases, are a constellation of biological, psychological, and social factors there is still further need to address existing issues with under-treatment of patients suffering from chronic pain resulting from shortened hospital stays and lack of at-home monitoring and telemedicine. As outlined in IOM's Relieving Pain in America report: In 2007, almost half of Emergency Department patients presented with pain that was severe 22% or moderate 23%. (Niska et al, National Hospital Ambulatory Medical Care Survey: 2007 emergency department summary. National Health Statistics Reports 26. Hyattsville, Md.: National Center for Health Statistics) Chest or abdominal pain was the leading reason for the visit among those aged 15-64, while chest or abdominal pain plus shortness of breath was the leading reason for the visit among those 65 and older. There were 10 million inpatient surgeries and 17.4 million hospital outpatient surgeries in 2009 (AHA (American Hospital Association). 2011. Trendwatch chartbook 2011. Tables 3.1 and 3.4. http://www.aha.org/aha/research-and-trends/chartbook/index.html (accessed Mar. 3, 2011)). Between 10 and 50 percent of people having regularly performed surgical operations—groin hernia repair, breast and thoracic surgery, leg amputation, and coronary artery bypass surgery—go on to experience chronic pain, often due to damage to nerves in the surgical area during the procedure (Kehlet, et al, Persistent postsurgical pain: Risk factors and prevention. Persistent postsurgical pain: Risk factors and prevention. Lancet. 2006; 367(9522):1618-1625.). Today's shorter hospital stays—down, on average, from 7.2 days in 1989 to 5.4 days in 2009 (AHA, 2011)—and the trend toward outpatient surgery may not permit sufficient opportunity to assess patients' postsurgical pain or establish an appropriate course of postoperative analgesia (perhaps one that can be administered at home), shown to be effective in hip and knee replacement, for example (Schug et al. Chronic pain after surgery or injury. 2011 Pain Clinical Updates 19. Seattle, Wash.: International Association for the Study of Pain). There is currently no way to monitor an out-patient's response to pharmaceutical treatment and the effectiveness of treatment related to pain and other related chronic disease states.        
Recent improvements in sensor technology, powerful and miniaturized micro-controllers, systems on a chip (SOCs), low energy wireless communication, and power management add up to the opportunity for new wearable devices that allow for long-term, at-home, patient monitoring of physiologic measurements via patient worn sensors, cloud computing for data storage and analysis, and integration with networks and mobile devices provide communication with healthcare providers and healthcare systems. What is not measured in these devices of the prior art is a measurement of the severity of pain that a patient is experiencing either due to an immediate injury or as a chronic result of disease or other infirmary. Using the pain measurement and diagnostic system (PMD) of the present invention, pain is objectively measured to provide currently unavailable biophysical information that will assist in diagnosis, the selection and validation of treatments, and may provide patient incentives to continue in performing effective treatments. By tracking and evaluating biophysical measurements, “pain matrix” activity in the form of a pain modulatory circuit with inputs that arise in multiple areas including cortical sites, the rostral anterior cingulate cortex (rACC), pregenual cingulate cortex, (pCC), somatosensory cortex 1 and 2, the thalamus and hypothalamus, insula, the amygdala, periaqueductal gray region (PAG), and additional descending pathway structures, and vagal tone may be correlated to determine stress, cognition, emotion, disease states, and evaluation of threat to determine pain state, modulation of pain, level of health and healing, and the vulnerability toward illness of a patient (Ossipov et al. Central Modulation of Pain. The Journal of Clinical Investigations: November 2010; 120(11): 3779-3787.)
Pain measurements may also assist physicians in prescribing proper dosage based on the patient's reaction to medication. Patients are receiving inadequate access to pain medications due to the well-publicized abuse of opioids and the subsequent reluctance of the many in the medical community to write prescriptions for non-institutionalized patients. According to researchers at the CDC, to reverse the epidemic of opioid drug overdose deaths and prevent opioid-related morbidity, efforts to improve safer prescribing of prescription opioids must be intensified (Paulozzi L J, Jones C, Mack K, Rudd R. Vital signs: overdoses of prescription opioid pain relievers—United States, 1999-2008. MMWR Morb Mortal Wkly Rep 2011; 60:1487-92). Between 2013 and 2014, the age-adjusted rate of death involving synthetic opioids, other than methadone (e.g., fentanyl) increased 80% (Rudd et al. Increases in Drug and Opioid Overdose Deaths—United States, 2000-2014. CDC: Morbidity and Mortality Weekly Report (MMWR). Jan. 1, 2016/64(50); 1378-82). In 2014, there were approximately one and a half times more drug overdose deaths in the United States than deaths from motor vehicle crashes (CDC. Wide-ranging online data for epidemiologic research (WONDER). Atlanta, Ga.: CDC, National Center for Health Statistics; 2015. Available at http://wonder.cdc.gov). Adequate pain treatment and follow-up may be thwarted by a mix of uncertain diagnosis and societal stigma consciously or unconsciously applied to people reporting pain, particularly when they do not respond readily to treatment (TOM, 2011).
There is currently no objective measure for pain and as a result physicians struggle to both diagnose and treat pain. A pain monitor would address this major health crisis by facilitating healthcare providers' prescribing of opioid pain relievers; in particular, prescribing the appropriate dose. American Geriatrics Society cites delays in access to prescribed opioids for nursing home patients, including those who are terminally ill, and the American Cancer Society has recognized the frequent inaccessibility of opioids necessary for treating some pain (TOM, 2011). According to the White House action plan, between 2000 and 2009, the number of opioid prescriptions dispensed by retail pharmacies grew by 48 percent—to 257 million. However, based on increased regulations to limit opioid abuse, twenty-nine percent of primary care physicians and 16 percent of pain specialists report they prescribe opioids less often than they think appropriate because of concerns about regulatory repercussions (Breuer et al, Pain management by primary care physicians, pain physicians, chiropractors, and acupuncturists: A national survey. Southern Medical Journal 2010 103(8):738-747).
Accurate medication dosage, early intervention, and physician education are necessary. The following is a list of potential savings from improvements in pain prevention, care, education, and research per IOM 2011 Relieving Pain in America report:                better treatment of acute pain, through education about self-management and better clinical treatment, in order to avoid the progression to chronic pain, which is more difficult and more expensive to treat and generates high health care utilization;        reductions in health problems and complications of other physical and mental diseases and conditions associated with chronic pain that also are expensive to treat;        more cost-effective care of people with chronic pain when self-management and multimodal approaches are used more often, primary care physicians are educated and empowered to treat most people with pain appropriately, and unnecessary diagnostic tests and procedures and referrals to specialists are avoided;        better tailoring of treatment to individuals based on new research findings and integration of those findings into patterns of care. Patient Controlled Analgesia (PCA) devices which enable the patient to self-administer pain medicine are used to administer medications in institutional settings. While there is currently no commercially available way to objectively measure pain, and rising concern over abuse of opioids and other prescriptions, PCA's are utilized and do have advantages. Research shows PCA is superior to intermittent injection of pain medication, even by the IV route (D'Arcy, Y. (2007). Pain pointers: Safe pain relief at the push of a button. Nursing Made Incredibly Easy, 5(5), 9-12). Patients use less narcotic, do not have to wait for the nurse to bring the medication, and have greater overall satisfaction with better analgesia and lower pain scores than patients who request analgesia from the nursing staff (Smeltzer, S., et al. (2008). Textbook of medical surgical nursing (11th ed.). Philadelphia: Lippincott). By controlling pain, patients can move more readily, take deep breaths and ambulate earlier, reducing the risk of post-operative complications (D'Arcy, Y. (2008). Keep your patient safe during PCA. Nursing, 38(1), 50-55).        
Despite these advantages there are negatives. For example, they cannot be readily used, if at all, for infants, toddlers, and other who cannot operate the device due to either a physical disability such as a spinal cord injury or individuals unable or unwilling to understand instructions for use. Patients who are obese or asthmatic, or those taking drugs that potentiate opiates, such as sedatives or hypnotics, muscle relaxants and antiemetics, should not use PCA. Patients with sleep apnea should not use PCA (D'Arcy, Y. (2011). New thinking about postoperative pain management. OR Nurse, 51(11): 28-36). Also, current PCA devices continue to operate based upon the subjective measure of self-assessment. Without a means to normalize patient self-assessment inconsistent treatment remains an issue for patients. PCA combined with an objective measure for pain using the PainTrace medical devices and components and features of the pain measurement and diagnostic system (PMD) of the present invention may alleviate many existing issues.